This section presents data and statistics on household crowding in New Zealand. Household crowding increases the risk of infectious diseases spreading, particularly among children.
Household crowding is defined as needing one or more bedrooms; severe household crowding is defined as needing two or more bedrooms. Household crowding is measured with Census data, using the Canadian National Occupancy Standard. See information about the data below.
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In 2013, 9.7 percent of New Zealanders (366,000 people) lived in a crowded house (Figure 1). This is a decrease of over 2 percent compared to 1991, when household crowding affected 11.9 percent of the population.
In 2013, 3.1 percent of people lived in severely crowded houses (needing 2 or more bedrooms), a slight decrease of 0.4 percent from 3.5 percent in 1991.
Many Māori and Pacific people live in crowded houses. In 2013, household crowding affected:
- 40 percent of Pacific people
- 20 percent of Māori
- 4 percent of people of European ethnicity.
The proportion of people living in crowded houses decreased in all ethnic groups from 1991 to 2013. However, large ethnic differences still remain.
Children (0–14 years) are disproportionately affected by household crowding in New Zealand (Figure 2).
About one in seven children (15.2 percent) lived in crowded houses and a third of these children (4.9 percent) lived in severely crowded households (needing two or more bedrooms).
Māori and Pacific children were more affected by household crowding than children of other ethnic groups. Over 40 percent of Pacific children (43 percent) and 24 percent of Māori children lived in crowded houses in 2013.
Geographically, household crowding is worse in the North Island, where over 11 percent of the population lived in crowded households in 2013. In the South Island, less than 5 percent of the population lived in crowded households in 2013 (Figure 3).
In 2013, Kawerau District had the highest proportion of people living in crowded households (16.4 percent), followed by Opotiki District (15.9 percent) and Porirua City (15.0 percent) (Figure 3).
Figure 3: Percentage of population living in crowded households, by territorial authority (TA), 2013
In 2013, Counties Manukau District Health Board (DHB) had the highest proportion of population living in crowded households (21.2 percent), followed by Auckland DHB (15.0 percent) and Tairawhiti DHB (14.1 percent) (Figure 4).
Figure 4: Percentage of population living in crowded households, by District Health Board (DHB), 2013
Household crowding is very unevenly distributed in New Zealand. Along with children and Māori and Pacific ethnicity, risk factors for household crowding include :
- living in rental houses
- multi-family households
- low equivalised household income
- being unemployed
- lack of educational qualifications.
Household crowding can increase the spread of infectious diseases. In particular, household crowding is a risk factor for :
- lower respiratory tract infections (including pneumonia and RSV bronchiolitis)
- meningococcal disease
- Haemophilus influenzae (Hib) disease
- Hepatitis A
- Helicobacter pylori infection
Evidence also suggests that household crowding is a risk factor for upper respiratory tract infections and trachoma (eye infections) .
Children are more at risk from these diseases. Some children are disproportionately affected by these diseases: infants, Māori and Pacific children, and children living in the most deprived areas.
In 2007–2011, an estimated 1,343 hospital admissions for infectious diseases were caused by household crowding annually in New Zealand .
Crowded households were an important risk factor for Māori and Pacific, and especially for meningococcal disease.
The main conditions contributing to attributable hospital admissions were: bronchiolitis from respiratory syncytial virus (RSV), pneumonia/lower respiratory tract infections, upper respiratory tract infections, Helicobacter pylori infections and gastroenteritis.
Source: Census (1991, 1996, 2001, 2006, 2013). Results for household crowding published in The Distribution of Household Crowding in New Zealand: An analysis based on 1991 to 2006 Census data .
Definition: A household is generally considered overcrowded if at least one more bedroom is needed. We used the following definitions for this indicator:
- household crowding: at least one more bedroom is needed (1+ bedroom deficit)
- severe household crowding: at least two more bedrooms is needed (2+ bedroom deficit).
In New Zealand, the number of bedrooms needed is defined using the Canadian National Occupancy Standard. These criteria are:
- there should be no more than two people per bedroom
- children younger than 5 years of different sexes may reasonably share a bedroom
- children 5 years or older of the opposite sex should not share a bedroom
- children younger than 18 years and of the same sex may reasonably share a bedroom
- household members 18 years or over should have a separate bedroom, as should parents or couples.
1. Baker MG, Goodyear R, Telfar Barnard L, Howden-Chapman P. 2012. The Distribution of Household Crowding in New Zealand: An analysis based on 1991 to 2006 Census data. Wellington: He Kainga Oranga / Housing and Health Research Programme, University of Otago, Wellington. Available online: http://www.healthyhousing.org.nz/publications/
2. Baker MG, McDonald A, Zhang J, Howden-Chapman P. 2013. Infectious Diseases Attributable to Household Crowding in New Zealand: A systematic review and burden of disease estimate. Wellington: He Kainga Oranga/ Housing and Health Research Programme, University of Otago. Available online: http://www.healthyhousing.org.nz/publications